Germ line-specific DNA sequences are present on all five micronuclear chromosomes in Tetrahymena thermophila

The development of the macronucleus from the zygotic micronucleus in the ciliated protozoan Tetrahymena spp. involves the elimination of specific DNA sequences (M. C. Yao and M. Gorovsky, Chromosoma 48:1-18 1974). The present study demonstrates that micronucleus-specific DNA is present on all five of the micronuclear chromosomes. Fragments of micronuclear DNA from Tetrahymena thermophila were cloned in the plasmid vector pBR322. A procedure was developed to examine the organization of the cloned sequences in micro- and macronuclear DNA without nick translating each individual probe. Twenty-three percent of randomly selected DNA sequences examined by this method were micronucleus (germ line) specific. They were all members of families of repeated sequences. Hybridization of six micronucleus-specific DNA sequences to micronuclear DNA from nullisomic strains of T. thermophila, which are lacking one or more pairs of chromosomes in the micronucleus, suggested that these sequences are present on several chromosomes. One micronucleus-specific sequence was shown by in situ hybridization to be present on all five of the micronuclear chromosomes.

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A method for mapping germ line sequences in Tetrahymena thermophila using the polymerase chain reaction.

Genetics ◽

10.1093/genetics/137.1.95 ◽

1994 ◽

Vol 137 (1) ◽

pp. 95-106 ◽

Cited By ~ 1

Author(s):

D Cassidy-Hanley ◽

M C Yao ◽

P J Bruns

Keyword(s):

Polymerase Chain Reaction ◽

Dna Sequences ◽

Tetrahymena Thermophila ◽

Germ Line ◽

Repetitive Sequences ◽

Mapping Technique ◽

Ciliated Protozoan ◽

Chain Reaction ◽

Polymerase Chain ◽

Template Dna

Abstract A method for mapping DNA sequences to specific germinal chromosomes in the ciliated protozoan Tetrahymena thermophila has been developed. This mapping technique (PCR mapping) utilizes the polymerase chain reaction and template DNA derived from nullisomic strains to directly assign micronuclear DNA sequences to specific micronuclear chromosomes. Using this technique, a number of unique sequences and short repetitive sequences flanked by unique sequences have been mapped to four of the five germinal chromosomes.

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Elimination of DNA sequences during macronuclear differentiation in Tetrahymena thermophila, as detected by in situ hybridization

Chromosoma ◽

10.1007/bf00344591 ◽

1982 ◽

Vol 85 (1) ◽

pp. 11-22 ◽

Cited By ~ 32

Author(s):

Ruth Weaver Yokoyama ◽

Meng-Chao Yao

Keyword(s):

In Situ Hybridization ◽

Dna Sequences ◽

Tetrahymena Thermophila

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DNA sequence mapping in interphase and metaphase chromosomes by fluorescence in situ hybridization

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122885 ◽

1992 ◽

Vol 50 (1) ◽

pp. 496-497

Author(s):

Barbara Trask ◽

Susan Allen ◽

Anne Bergmann ◽

Mari Christensen ◽

Anne Fertitta ◽

...

Keyword(s):

In Situ Hybridization ◽

Dna Sequence ◽

Dna Sequences ◽

Dual Band ◽

Nick Translation ◽

Metaphase Chromosomes ◽

Band Pass ◽

Texas Red ◽

Fluorescent Spot

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.

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Chromosomal organization of a sequence related to LTR-like elements of Ty1-copia retrotransposons in Avena species

Genome ◽

10.1139/g99-007 ◽

1999 ◽

Vol 42 (4) ◽

pp. 706-713 ◽

Cited By ~ 10

Author(s):

Concha Linares ◽

Antonio Serna ◽

Araceli Fominaya

Keyword(s):

In Situ Hybridization ◽

Diploid Species ◽

D Genome ◽

Specific Sequence ◽

Chromosomal Organization ◽

Intergenomic Translocations ◽

A Genome ◽

Slot Blot Analysis ◽

Copia Retrotransposons

A repetitive sequence, pAs17, was isolated from Avena strigosa (As genome) and characterized. The insert was 646 bp in length and showed 54% AT content. Databank searches revealed its high homology to the long terminal repeat (LTR) sequences of the specific family of Ty1-copia retrotransposons represented by WIS2-1A and Bare. It was also found to be 70% identical to the LTR domain of the WIS2-1A retroelement of wheat and 67% identical to the Bare-1 retroelement of barley. Southern hybridizations of pAs17 to diploid (A or C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) oat species revealed that it was absent in the C diploid species. Slot-blot analysis suggested that both diploid and tetraploid oat species contained 1.3 × 104 copies, indicating that they are a component of the A-genome chromosomes. The hexaploid species contained 2.4 × 104 copies, indicating that they are a component of both A- and D-genome chromosomes. This was confirmed by fluorescent in situ hybridization analyses using pAs17, two ribosomal sequences, and a C-genome specific sequence as probes. Further, the chromosomes involved in three C-A and three C-D intergenomic translocations in Avena murphyi (AC genomes) and Avena sativa cv. Extra Klock (ACD genomes), respectively, were identified. Based on its physical distribution and Southern hybridization patterns, a parental retrotransposon represented by pAs17 appears to have been active at least once during the evolution of the A genome in species of the Avena genus.Key words: chromosomal organization, in situ hybridization, intergenomic translocations, LTR sequence, oats.

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